Battery management system and battery cell array

ABSTRACT

A battery cell array includes a plurality of battery banks, each battery bank including a two-dimensional m-by-n or higher-order matrix of battery cells; a row address decoder configured to activate selected address lines, the address lines including a wordline(s); a column address decoder configured to activate selected address lines, the address lines including a bitline(s); an address decoder(s), if required, configured to activate a select signal(s) to select an additional address line(s) for a more than two-dimensional matrix of battery cells; a controller configured to directly or indirectly activate a bank select signal(s) to select a battery bank of the plurality of battery banks.

CROSS REFERENCE TO PRIOR APPLICATION

This application is a divisional Application of U.S. patent applicationSer. No. 15/874,902 filed on Jan. 19, 2018 under 35 U.S.C. § 120, theentire contents of which are incorporated herein by reference.

BACKGROUND Field of the Invention

One or more embodiments of the present invention relate to batterymanagement system and battery cell array.

Description of Related Art

When a battery is charged and discharged once, it is called a chargecycle. Battery capacity degrades as the number of charge cyclesincreases. Battery life is measured in charge cycles, with an industrystandard of cycles to 80% capacity often used as a benchmark. There arefour major factors that shorten the battery life: high temperature;overcharging or high voltage; deep discharging or low voltage; and highdischarge or charge current.

For example, Lithium battery voltage must not exceed preset batterythreshold levels such as the maximum charge voltage; failure to do somay shorten battery life or permanently damage the battery itself. Insome batteries, a battery management system (BMS) is used to controlcharging voltage so that the maximum charge voltage and/or temperatureare never exceeded.

High voltage can also lead to another limit, called the calendar life.As a battery ages, the layer where the exchange of ions happensincreases and internal resistance increases. At some point, the layerbecomes large enough that no ions can pass and the battery life ends.This kind of battery lifetime limit is worsened the longer the cell iskept at maximum voltage and high temperature. The idea here is to avoidmaximum voltage and high temperature for extended periods of time.

To increase cell calendar life, overvoltage and high temperature must beavoided. In addition, at the other end of cell voltage and charge, formaximum cycle life, deep discharge must be avoided as well. Experimentaldata suggest an inverse power-law dependence of the cycle life on theDoD, such that a four-fold lifetime gain is achieved going from 100% to50% DoD, where the DoD (depth of discharge) means a degree of beingdischarged. For maximum battery cycle life, 100% DoD must be avoided.Another description is called the state of charge (SoC). If a cell isfully charged, it is said to be at 100% SoC. The SoC works like a fuelgauge.

Not all Battery Cells are Created Equal

A battery system usually consists of multiple battery cells. In general,not all batter cells are produced identical and each battery cell canvary greatly in its native endurance capability having a finitelifespan. A battery cell further degrades in voltage and charge-storingcapability as the cell repeats being charged-and-discharged due todeterioration in the chemical, physical, mechanical and electricalproperties of the materials, and the slow erosion of the insulators as aresult of repeated charging and discharging processes to and from thebattery cell, respectively. Over time, the cell degrades and its abilityto hold electrical charge diminishes.

A finite lifetime dictated by the number of repeatedcharging-and-discharging processes is termed as the charge cycle that abattery cell can endure. As mentioned above, the term is typically usedto specify a battery's expected life, as the number of charge cyclesaffecting life more than the mere passage of time. The act ofdischarging the battery fully before recharging may be called “deepdischarge”; partially discharging then recharging may be called “shallowdischarge”.

Charged and Discharged and Obsolete Battery Cells

There are several states of battery cells in the present invention suchas charged, discharged and obsolete cells. Charged cells are charged upto a certain high threshold voltage level that is less than or equal toits maximum chargeable voltage level in a certain period of time.Discharged cells are discharged down to a low threshold voltage levelthat is more than or equal to its minimum prohibitive level or completeddischarged level. Obsolete cells are battery cells that cannot becharged up to a certain voltage level within a certain period of time ordegrade and lose their capability to hold electric charge due to agingor damages.

SUMMARY

One or more embodiments of the present invention include a batterymanagement system to avoid a premature wear-out of a heavily usedbattery cell(s).

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented embodiments.

According to an embodiment of the present invention, a batterymanagement system includes: a battery cell array including a pluralityof battery cells; a charger selector array connected electrically to thebattery cell array to charge the battery cells; an analyzer arrayconfigured to monitor a condition or status of the battery cells andreports a condition or status of each battery cell; a battery outputarray connected electrically to the battery cell array to provide avoltage of battery cells as a whole or in part; and a controllerconfigured to control operation of the charger selector array and/or thebattery output array according to the reported condition or status fromthe analyzer array, and configured to selectively activate a selectsignal(s) to choose a battery cell(s) in a battery array.

The condition or status may include the amount or degree of beingcharged and discharged, a number of times of being charged anddischarged, whether working properly or not, whether being able to becharged up to a certain voltage level within a certain time, a maximumchargeable voltage, and a charging voltage level for each battery cell.

The condition or status may include information of whether a certainbattery cell has a fault that the battery cell is not rechargeableenough up to a certain pre-defined voltage level within a certain time.

The controller is configured to tune the battery cell array to meet aspecific endurance levels required for a variety of applications byreconfiguring the battery cell array, and/or the charger selector arrayand/or the battery output array accordingly.

The controller is configured to newly redirect the charging anddischarging processes to a different battery cell(s) to avoid apremature wear-out of a too heavily used battery cell(s).

The controller is configured to exclude an obsolete cell in selection asa normal cell for valid battery operation and replace the obsolete cellwith a candidate cell selected from a pool of redundant cells byreconfiguring the battery cell array, and/or the charger selector arrayand/or the battery output array accordingly.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to enable a spare or redundant battery cell(s) to beelectrically and/or mechanically connected to a given battery cellnetwork in serials and/or parallel, wherein a battery cell(s) from theactive pool is already connected in serials and/or parallel, to achievequick increase in voltage or power at the battery outputs in BOOSTbattery mode.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to work with fewer active cells by electrically and/ormechanically disconnecting an active cell(s) from a given battery cellnetwork, wherein battery cells from the active pool are alreadyconnected in serials and/or parallel, to achieve quick decrease involtage or power at the battery outputs in LESSENING battery mode.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to work with fewer active cells or a different batterycell(s) available from other pools such as the charged pool or redundantpool by electrically and/or mechanically disconnecting an overheatedactive cell(s) and/or replacing an overheated active cell(s) with aless-heated candidate cell(s) from other pools in a given battery cellnetwork to achieve quick decrease in temperature based on thetemperature information reported from a temperature sensor(s) placed ona battery cell(s) and/or the battery system in thermal THROTTLINGbattery mode.

The battery cell may be traced and/or selected in a queue or pool, and adata structure for the queue or pool can be stored in either off-deviceor on-device.

The battery cell in a battery array of battery cells may be classifiedinto one of pools such as an active pool, a discharged pool and acharged pool, wherein the active pool consists of battery cellselectrically charged and selected to provide electric power to thebattery output terminals, the discharged pool consists of battery cellsdeeply or shallowly discharged and requiring to be recharged to beactive, wherein the charged pool consists of battery cells chargedenough and ready to be active. When a battery cell is or gets faulty,the cell becomes an obsolete one excluded from the active, charged, anddischarged pools mentioned above and/or maybe belonged to another poollike an obsolete pool further, if necessary.

According to an embodiment of the present invention, a battery cellarray includes: a plurality of battery banks, each battery bankincluding a two-dimensional m-by-n or higher-order matrix of batterycells; a row address decoder configured to activate selected addresslines such as a wordline(s); a column address decoder configured toactivate selected address lines such as a bitline(s); an addressdecoder(s), if required, configured to activate a select signal(s) toselect another additional address line(s) for a more thantwo-dimensional matrix of battery cells; and a controller configured toactivate a bank select signal(s) to select a battery bank(s) of theplurality of battery banks.

The m is a number of rows and the n is a number of columns.

The controller is configured to newly redirect the charging anddischarging processes to a different battery cell(s) to avoid apremature wear-out of a heavily used battery cell(s).

The controller is configured to exclude an obsolete cell in selection asa normal cell for valid battery operation and replace the obsolete cellwith a candidate cell selected from a pool of redundant cells byreconfiguring the matrix of battery cells, and/or the charger selectorarray and/or the battery output array accordingly.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to enable a spare or redundant battery cell(s) to beelectrically and/or mechanically connected to a given battery cellnetwork in serials and/or parallel, wherein a battery cell(s) from theactive pool is already connected in serials and/or parallel, to achievequick increase in voltage or power at the battery outputs in BOOSTbattery mode.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to work with fewer active cells by electrically and/ormechanically disconnecting an active cell(s) from a given battery cellnetwork, wherein battery cells from the active pool are alreadyconnected in serials and/or parallel, to achieve quick decrease involtage or power at the battery outputs in LESSENING battery mode.

The controller is configured to allow the battery cell array to bereconfigured, and/or the charger selector array and/or the batteryoutput array to work with fewer active cells or a different batterycell(s) available from other pools such as the charged pool or redundantpool by electrically and/or mechanically disconnecting an overheatedactive cell(s) and/or replacing an overheated active cell(s) with aless-heated candidate cell(s) from other pools in a given battery cellnetwork to achieve quick decrease in temperature based on thetemperature information reported from a temperature sensor(s) placed ona battery cell(s) and/or the battery system in thermal THROTTLINGbattery mode.

The battery cell in the two-dimensional m-by-n or higher-order matrix ofbattery cells may be traced or selected through a queue or pool, and adata structure for the queue or pool may be stored in either off-deviceor on-device.

The battery cell in the two-dimensional m-by-n or higher-order matrix ofbattery cells may be classified into one of pools such as an activepool, a discharged pool and a charged pool, wherein the active poolconsists of battery cells electrically charged and selected to provideelectric power to the battery output terminals, the discharged poolconsists of battery cells deeply or shallowly discharged and requiringto be recharged to be active, wherein the charged pool consists ofbattery cells charged enough and ready to be active. When a battery cellis or gets faulty, the cell becomes an obsolete one excluded from theactive, charged, and discharged pools mentioned above and/or maybebelonged to another pool like an obsolete pool further, if necessary.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an analogy of battery cell connectivity with a chain inwhich the links represent the cells of a battery connected in series.

FIG. 2 shows a serial or series connection of four cells.

FIG. 3 shows a serial connection with one faulty cell.

FIG. 4 shows a parallel connection of four cells.

FIG. 5 shows a parallel connection with one faulty cell.

FIG. 6 shows a serial and parallel connection of four cells.

FIG. 7 is a drawing of a battery cell array according to an embodimentof the present invention.

FIG. 8 is a conceptual drawing of a battery management system accordingto an embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings, wherein like referencenumerals refer to like elements throughout. In this regard, the presentembodiments may have different forms and should not be construed asbeing limited to the descriptions set forth herein. Accordingly, theembodiments are merely described below, by referring to the figures, toexplain aspects of the present description.

Hereinafter, a battery device according to an exemplary embodiment ofthe present invention will be described with reference to theaccompanying drawings.

Battery Cell and Pack

Batteries achieve the desired operating voltage by connecting severalcells in series; each cell adds its voltage potential to derive at thefinal terminal voltage. Parallel connection attains higher capacity byadding up the total ampere-hour (Ah).

Some battery packs may consist of a combination of series and/orparallel connections. For example, laptop batteries commonly have four3.6V Li-ion cells in series to achieve a nominal voltage 14.4V and twoin parallel to boost the capacity from 2,400 mAh to 4,800 mAh. Suchconfiguration called 4s2p means that there are four battery cells inseries and two in parallel. Insulating foil between the cells preventsthe conductive metallic skin from causing an electrical short.

Most battery chemistries lend themselves to series and parallelconnection. It is important to use the homogeneous battery type withequal voltage and capacity (Ah) and never to mix different makes andsizes. A weaker cell would cause an imbalance and reduce the life spanand use time of a battery device.

FIG. 1 shows an analogy of battery cell connectivity with a chain inwhich the links represent the cells of a battery connected in series.

This is especially critical in a series configuration because a batteryis only as strong as the weakest link in the chain.

A weak cell may not fail immediately but will get exhausted more quicklythan the strong ones when in continued use. On charge, the low cellfills up before the strong ones because there is less to fill and itremains over-charged longer than the others. On discharge, the weak cellempties first and gets hammered by the stronger neighbors. Cells inmulti-packs must be matched, especially when used under heavy loads.

The chain links represent cells in series to increase voltage anddoubling a link denotes parallel connection to boost current loading.

Series or Serial Connection

Portable equipment needing higher voltages use battery packs with two ormore cells connected in series.

FIG. 2 shows a series or serial connection of four cells.

Referring to FIG. 2, a battery pack with four 3.6V Li-ion cells inseries is represented, known as 4s, to produce 14.4V nominal. Incomparison, a six-cell lead acid string with 2V/cell will generate 12V,and four alkaline with 1.5V/cell will give 6V.

Adding cells in a string increases the voltage and keeps the capacitysame.

Cordless power tools run on 12V and 18V batteries and high-end modelsuse 24V and 36V. Most e-bikes come with 36V Li-ion, some are 48V. Thecar industry wanted to increase the starter battery from 12V (14V) to36V, better known as 42V, by placing 18 lead acid cells in series.Logistics of changing the electrical components and arcing problems onmechanical switches derailed the move. Some mild hybrid cars run on 48VLi-ion and use DC-DC conversion to 12V for their electrical systems.Starting the engine is often done by a separate 12V lead acid battery.On the other hand, early hybrid cars ran on a 148V battery and electricvehicles are typically 450-500V. Such batteries need more than 100Li-ion cells connected in series. The Teslar 85 further devours over7,000 18650 cells to make up to the 90 KWh pack.

High-voltage batteries require careful cell matching, especially whendrawing heavy loads or when operating at cold temperatures. Withmultiple cells connected in a string, the possibility of one cellfailing is real and this would cause a failure. To prevent this fromhappening, a solid state switch in some large packs bypasses the failingcell to allow continued current flow, albeit at a lower string voltage.

Cell matching is a challenge when replacing a faulty cell in an agingpack. A new cell has a higher capacity than the others, causing animbalance. Welded construction adds to the complexity of the repair, andthis is why battery packs are commonly replaced as a unit.

High-voltage batteries in electric vehicles, in which a full replacementwould be prohibitive, divide the pack into modules, each consisting of aspecific number of cells. If one cell fails, only the affected module isreplaced. A slight imbalance might occur if the new module is fittedwith new cells.

FIG. 3 shows a serial connection with one faulty cell.

FIG. 3 describes a battery pack in which “cell 3” produces only 2.8Vinstead of the full nominal 3.6V. With depressed operating voltage, thisbattery reaches the end-of-discharge point sooner than a normal pack.The voltage then collapses and the device turns off with a “Low Battery”message.

Faulty cell lowers the total voltage and cuts the equipment offprematurely.

Batteries in drones and remote controls for a hobbyist requiring highload current often exhibit an unexpected voltage drop if one cell in astring becomes weak. Drawing maximum current stresses frail cells,leading to a possible crash. Reading the voltage after a charge does notidentify this anomaly; examining the cell-balance or checking thecapacity with a battery analyzer will do.

Parallel Connection

FIG. 4 shows a parallel connection with one faulty cell.

If higher currents are needed and larger cells are not available or donot fit the design constraint, one or more cells can be connected inparallel. Most battery chemistries allow parallel configurations withlittle side effect. FIG. 4 illustrates four cells connected in parallelin a 4p arrangement. The nominal voltage of the illustrated pack remainsat 3.60V, but the capacity (Ah) and runtime are increased fourfold.

A cell that develops high resistance or opens is less critical in aparallel circuit than in a series configuration, but a failing cell willreduce the total load capability. It's like an engine only firing onthree cylinders instead of on all four. An electrical short, on theother hand, is more serious as the faulty cell drains energy from theother cells, possibly causing a fire hazard. Most so-called electricalshorts are mild and manifest themselves as elevated self-discharge.

FIG. 5 shows a parallel connection with one faulty cell.

An electrical short can occur through reverse polarization or dendritegrowth. Large packs often include a fuse that disconnects the failingcell from the parallel circuit if it were to short.

A weak cell will not affect the voltage but provide a low runtime due toreduced capacity. A shorted cell could cause excessive heat and become afire hazard. On larger packs a fuse prevents high current flow byisolating the faulty cell.

Series/Parallel Connection

The series and parallel configuration shown in FIG. 6 enables designflexibility and achieves the desired voltage and current ratings with agiven 18650 standard cell unit (3.6V 3400 mAh in this example). Thetotal power is the product of voltage-times-current; four 3.6V (nominal)cells multiplied by 3,400 mAh produce 12.24 Wh. Four energy cells of3,400 mAh each can be connected in series and parallel as shown to get7.2V nominal and 12.24 Wh. The slim cell allows flexible pack design buta protection circuit is needed.

Li-ion lends itself well to series/parallel configurations but the cellsneed monitoring to stay within voltage and current limits. Integratedcircuits for various cell combinations are available to supervise up to13 Li-ion cells. Larger packs need custom circuits, and this applies toe-bike batteries, hybrid cars and the Tesla Model 85 that devours over7,000 18650 cells to make up the 90 kWh pack.

FIG. 6 shows a serial and parallel connection of four cells.

The configuration provides maximum design flexibility. Paralleling thecells helps in voltage management.

Safety Devices in Series and Parallel Connection

Mechanical temperature sensors such as thermometers, electricaltemperature sensors such as Positive Temperature Coefficient (PTC) andNegative Temperature Coefficient (NTC) thermistors, and Charge InterruptDevices (CIDs) protect the battery from overcurrent and excessivepressure. While recommended for safety in a smaller 2- or 3-cell packwith serial and parallel configuration, these protection devices areoften being omitted in larger multi-cell batteries, such as those forpower tools. The NTC, PTC and CID work as expected to switch off thecell on excessive current and internal cell pressure; shutdown howeveroccurs in a cascade way. While some cells may go offline early, the loadcurrent causes excess current on the remaining cells. Such overloadcondition could lead to a thermal runaway before the remaining safetydevices activate.

Some cells may have built-in NTC and/or PTC and/or CID; these protectiondevices can also be added retroactively. Note that any safety device issubject to failure. In addition, the PTC induces a small internalresistance that reduces the load current.

1. Array Structure of Battery Management System

FIG. 7 is a drawing of a battery cell array and FIG. 8 shows aconceptual drawing of a battery management system according to anembodiment of the present invention.

Referring to FIG. 7 and FIG. 8, the present invention includes a batterycell array 110, a charger selector array 120, an analyzer array 130, abattery output array 140, a temperature sensor array 160 over thebattery cell array, and a controller 150.

The charger selector array 120 enables the power input sources (VDD andGND) to alternatively and/or concurrently charge the battery cellarray(s) to which multiple battery cells are attached. A chargerselector 121 is an electrical or mechanical switch that depending on thecharger selector 121 signals connects the power sources (VDD and GND) tothe power lines (PLs) 111 b so that the power input sources aredelivered to the selected the battery array(s) through PLs. The chargeselector(s) 121 turns off when the related battery cell(s) is indischarging mode.

A PL is placed and shared by two adjacent columns of the proposedbattery cell array along the column direction. The column select signalCS controls which column(s) of the array is connected to PL. Plural CSsignals can be implemented and activated in a time sharing fashion. Inthe figure, alternative assertion of CS0 and CS1 signals makes sure thateach PL carries one electrical polarity and protects the battery systemfrom being electrically shorted between the power input sources.

The battery cell array 110 is in a form of an m-by-n matrix, where m isthe number of rows and n is the number of columns. If necessary, thebattery cell matrix can be extended to be a higher-order matrix such asa three-dimensional matrix. For example, the battery cell array shown inFIG. 7 illustrates a single battery bank containing a 3-by-4 matrix orarray of battery cells where row addresses are formed from one or pluralwordlines (WLs) that are driven to activate one cell on each one of fourbitlines (BLs). A cell(s) in the battery cell array or matrix can beselected by activating both WL and BL. Each cell has a pair of switches111 a, one switch 111 a is controlled by WL and the other by BL, thatmake an electrical or mechanical connection or disconnection between thecell and the associated PL.

Note that the innate matrix or array form of battery cells can beextended to include more cell elements for larger size and capacitydepending on target applications if so desired. A number of benefitsappear when an electric battery is sized for long range. Alarger-capacity battery results in a lower average depth of dischargeand consequently longer cycle life and lower peak charge/discharge rate.If a battery pack is designed to have capacity providing long range, itis likely that daily charging will be at low depth of discharge. Theimpact of this on electric vehicle design, for example, is important. Itmeans that the route to long range or high capacity may also result inlower depth of discharge and longer life for a given battery chemistry.If maximum charging is limited to, say, 80% of its maximum capacityduring most operation, maximum voltage is avoided. If the battery packis also thermally controlled, reaching both maximum voltage and/or hightemperatures is avoided. In this way, controlled conditions can increasebattery life substantially.

In the battery cell array, two adjacent columns of the cell array shareone PL along the column direction. Plural (e.g., three in the figure)cells in each column can be connected to a PL at the column direction,but only one cell selected by both WL and BL asserted will get chargedfrom or discharged to the associated PLs at a time during the chargephase or discharge phase, respectively.

Battery cell 111 is a package that contains one single or multiplere-chargeable battery units. For example, the battery cell shown in FIG.4 consists of two 3.6V 3,400 mAh battery units connected in parallel.Battery cells in FIG. 7 selected by the forwarded row and columnaddresses inside the chosen bank (e.g., bank 0 in this example) aremarked in gray: cell (2,1), (3,2), (1,3), and (2,4), and the forwardedrow (WLs) and column (BLs) addresses are indicated in gray. Note that atleast one battery cell is selected at each column and the selected cellsare electrically or mechanically connected through the PLs placedintermediately in the array and their voltages are electricallyaccumulated along the row direction.

All or part of PLs run to the battery output array 140 where the inputvoltages carried from the PLs are reconstructed. A set of resultantoutput voltages driven by the battery cell arrays are partially and/orfully accumulated voltage levels with respect to a reference voltagelevel (i.e., OUTB) such as PartialOUT1, PartialOUT2, etc., and/or OUT,respectively.

The analyzer array 130 contains an analyzer or an array of analyzers andeach analyzer monitors the condition or status of a cell selected withthe asserted WL and BL in the column of interest. The analyzer mayreport the monitored information to the controller 150 that now tracesthe individual cell's condition or status that may include but notlimited to features such as the degree of charge or discharge of eachbattery cell (how much each battery cell is charged or discharged), thenumber of charge-and-discharge times (how many times the cell has beencharged and discharged), whether working properly or not, whether beingable to be charged up to a certain voltage level within a certain time,and a maximum chargeable voltage (how much the cell can be charged), anda charging level (how much the cell is charged) for each battery cell,and etc. in runtime. Further, a temperature sensor(s) 160 placed on abattery cell(s) and/or the battery array may report the temperatureinformation of the corresponding individual battery cell(s) or theentire battery array to the controller 150 in runtime as well.

Based on information reported from the analyzers 130 and temperaturesensors 160, the controller 150 may select which cell(s) to be chargedor discharged for the next cell accesses. Well-known algorithms such asRR (Round Robin) and/or LRU (Least Recently Used) and/or LFU (LeastFrequently Used) can be used to select a cell(s) from the charged ordischarged pool or group for discharging (power-providing to the outsideapplications) or charging accesses in normal, respectively.

FIG. 8 also illustrates the multiple overlapped phases of operation suchas command transport and decode, cell accesses in a bank, and outputsfrom the device.

Battery management system can have multiple battery banks as shown inFIG. 8, where each bank has its own battery cell arrays 110, row and/orcolumn address decoders, charger selector array 120, and analyzers array130 and battery output array 140. A single bank consists of pluralarrays of battery cells where a row address(es) is formed from one orplural wordlines (WLs) driven concurrently to activate one or multiplecell(s) on each one of thousands of bitlines (BLs). The battery outputsmay be combined with their counterparts in other banks so that thecombined battery outputs work as final battery outputs of the entirebattery system.

The battery system (or device) may contain an address register(s) thatis used to store a cell location(s) and control the command and/or dataflow within the system. The address may consist of separate row andcolumn addresses rather than a single address. In the case of separateaddresses, the address register may accordingly consist of separate rowand column address registers to control battery operation. Wordlines(WLs) and bitlines (BLs) can be driven concurrently or alternativelythrough a register(s) that holds the WL and/or BL addresses for acertain period of time. WL(s) and BL(s) are driven directly orindirectly, and concurrently or sequentially from the row and columndecoders, or row addresses and column addresses are buffered into theircorresponding registers that now drive the target WL(s) and BL(s). Inthe later case, the related row and/or column address registers areprogrammed sequentially or in parallel which may help to lower thehardware complexity and increase design efficiency by trading off therequired hardware resources such as internal bus width.

For a battery cell access command, an address(es) from the addressregister(s) is forwarded to the row address latch and decoder, and theaddress(es) is used to activate the selected address line(s) like WL orBL. Electric charge from the battery cell(s) selected by the activatedWL(s) and BL(s) is then discharged onto the corresponding power lines(PLs) 111 b. The PLs are fed into the input and output (I/O) gatingcircuit that produces partially and/or fully accumulated voltages out ofthe voltages associated with the PLs. The partial and/or full voltagesare now finally delivered to the outside world from the battery device.

Besides the row and column address decoders, at least one more addressdecoder, if required, activates a select signal(s) to select a furtheraddress line(s) when the order of a battery matrix of battery cells ismore than two-dimensional.

The controller 150 controls a bank select signal(s) to select a batterybank(s) of the plurality of battery banks.

Referring to FIG. 8, there can be multiple overlapped phases ofoperation for an abstract battery cell access command as follows: inphase one (Command transfer and decode), a command is transferredthrough the command and address buses and decoded by the device; inphase two (Cell access in Bank), electric charge is moved within a bank,either from a cell(s) to PL(s) or from PL(s) into the battery array(s);in phase three (Outputs from Device), the resultant voltage output(s)partially and/or fully accumulated out of individually placed voltage(s)on a PL(s) driven from the battery core array is fed onto the outputterminals of the device to be delivered to the outside world through theI/O gating. The output terminals may be connected to multiple banks ofbattery.

Other Advantages of the Present Invention

This present invention can dynamically reconfigure array connections ofbattery cells and thus help to efficiently manage the C rate of abattery by keeping the C-rate high during charge phase and low duringdischarge phase. The C rate is defined in units of C, where 1C means thebattery can be charged in one hour. If the battery is charged at 2C, thebattery may be charged in half an hour. Battery cells in this inventionare innately arranged in an array and dynamically configurable.Depending on a network configuration of active cells, fewer cellsconnected in parallel resulting in higher C-rate enables the batterydevice to get charged faster in the charging mode whereas more cellsconnected in parallel allow the same device to discharge higher currentand produce larger energy while individual cell with lower C-rate canstay within its C limit and last longer.

2. Active Pool, Discharged Pool, Charged Pool and Other Pools

There may be various pools (or groups or queues or bitmaps) of regularbattery cell(s) managed in battery: active, discharged, and chargedpools. Active pool contains an active battery cell(s) that is chargedand electrically hooked up in the battery array(s) and can immediatelyprovide electric power to the outside or applications; Discharged poolcontains a cell(s) that is deeply or shallowly discharged and needs tobe recharged to be active. Charged pool has a charged cell(s) that isready to be active. When a battery cell is or gets faulty, the cellbecomes an obsolete one excluded from the active, charged, anddischarged pools mentioned above and/or maybe belonged to another poollike an obsolete pool further, if necessary.

Once the controller 150 chooses a cell(s) in the charged pool toactivate, the controller 150 configures to make the cell(s) active andaccordingly updates its internal information maintained, for example, inan internal history table form. After a cell(s) from the discharged poolgets sufficiently charged to a certain voltage level within a time, thecontroller 150 moves the newly charged cell to the charged pool from thedischarged pool and then updates its internal information accordingly topoint to the new active cell location. A discharged cell being toodischarged to be active and its voltage level lowered down to a certainlevel is erased from the active cell pool, and assigned to thedischarged pool and made available as a candidate cell to be chargedlater.

Each battery cell can have its own history table. A history table ofsome sort can be kept for each cell in order to keep trace of itsbehaviors including but not limited to the number of charge (anddischarge) cycles (how many times it has been charged and discharged)that it has undergone, and/or charging time (how long it takes to getcharged up to a defined capacity (e.g., voltage or charge) level),and/or status (which pool it belongs to among active, charged,discharged, obsolete pools, etc.), and/or validity (whether it is avalid and regular, or faulty and obsolete cell), etc.

A battery cell(s) on the media can be tracked and/or selected in a RR(Round Robin) and/or LRU (Least Recently Used) and/or LFU (LeastFrequently Used) queue or pool of some sort. Data structures for thecorresponding queues themselves can be stored either off-device oron-device.

On battery devices, the techniques proposed in the present invention maybe implemented in hardware by a built-in microcontroller. On suchdevices, the techniques proposed in the present invention including wearleveling are transparent, and most conventional battery systems can beused on them as-is. The techniques proposed in the present invention canalso be implemented in software on the media, which may be alog-structured system in that the media may be treated as circular logsand selected to access the battery cells in sequential passes.

3. Wear Leveling

Wear leveling (also written as wear levelling) is a technique to prolongthe service life or lifespan of a battery device. Wear leveling ensureseven wear-out of all battery unit cells by equally distributing allcharge cycles across the media, thus resulting in increased endurance.In this way, no single cell prematurely fails due to a highconcentration of charge/discharge processes. Without wear leveling,applications would constantly charge and recharge only some part of thebattery cells which would quickly wear them out. Frequently usedlocations as a result will wear out quickly, while other locations willnot be used at all. Once a few cells reach their end of life, suchbatteries become inoperable.

In wear leveling, all new electric charge is written to a cell(s) thatbelongs to the discharged pool not maintaining a certain voltage level.A controller 150 selects a cell(s) from the discharge pool based onreported information such as the number of charge cycles that thecell(s) has already undergone. Wear leveling addresses the issue ofrepeated charge/discharge cycles to the same battery cell(s) byredirecting new charge/discharge processes to a different cell(s), thusavoiding a premature wear-out of a too heavily used battery cell(s).

Wear leveling treats battery as a system, rather than individual batterycells of media. The act of analyzing in runtime how each cell isbehaving (charging time and charging capability, etc) allows thecontroller 150 in a battery system to see whether the cell gets too agedor faulty. Further, being able to dynamically monitor how many timeseach individual cell gets charged-and-discharged allows the controller150 in the system to choose which cells should get more often chargedthan others. This enables the system to tune batteries to meet specificendurance levels required for a variety of applications. Obviously, thehigher the endurance the longer battery will be able to operate.

In wear leveling, the entire image is leveled. Unless otherwisespecified, all available and valid cells across the battery deviceparticipate in the wear-leveling operation. This rotational effectensures all valid cells to receive the same amount of wear and thedevice to continue to operate until most of the cells are near their endof life. Static wear leveling would be most often used in generalapplications.

4. Over-Provisioning or Redundancy

The over-provisioning technique sets aside extra (or redundant or dummy)physical battery cells for the use in case, resulting in higherendurance and better performance. Extra battery cells can be programmedto be connected to the main battery array if required. Similar to otherbattery cells, over-provisioned or reserved battery cells may be managedthrough a pool or group and/or bitmap, dedicatedly or combined with onesfor regular cells.

When a certain cell(s) in the main array becomes faulty (e.g., notchargeable enough up to a certain pre-defined capacity level within acertain time), a controller 150 in the battery management systemexcludes that obsolete cell in selection as a normal cell for validbattery operation and replace the obsolete cell with a candidate cellselected from a pool of redundant cells by reconfiguring the matrix ofbattery cells, and/or the charger selector array and/or the batteryoutput array accordingly. In this case, the controller 150 logicallyremaps the obsolete cell with the selected redundant cell and/orphysically reconfigures the network connection of the main batteryand/or extra cell(s) so that the selected redundant battery cell cansubstantially substitute for the obsolete cell. A redundant or extracell(s) is a spare cell(s) that is prepared for replacement of a batterycell that becomes too aged or damaged to work as a normal cell. Notethat each battery cell has a limited endurance (the maximum number ofbeing charged-and-discharged times) and capacity from when it ismanufactured, and naturally becomes aged and faulty, and degrades involtage and charge-holding capability while charging-and-dischargingprocesses are repeatedly performed. Differences further can exist amongall battery cells and each battery cell can have its own maximumendurance, and electrical, thermo dynamical and mechanicalcharacteristics ready set when manufactured. In other words, each cellcan have different endurance and lifespan due to PVT (process, voltageand temperature) variations. Manufacturers usually provide each productwith a minimum lifetime of product specifications. Since we don't knowwhich cell(s) becomes obsolete while maintaining an overall targetquality of the battery system in voltage and charging capacity,provision of a redundant cell(s) to replace an aged, obsolete or faultycell(s) in runtime if necessary helps to keep consistent overallquality, and extend the lifetime and reliability of the entire batterysystem.

Over-provisioning is the employment of more battery cell(s) thanpresented at an advertised user capacity. This extra cell(s) included inthe wear-leveling operation does not add to the battery charge capacitydisclosed to the user. The more over-provisioned space a battery systemhas, the longer it will last. As a rule of thumb, every time the batterydevice's over-provisioning is doubled the device's endurance is added by1×. Over-provisioning may simply come with cost. The end user is payingfor electrical chargeable space they cannot access in exchange for alonger battery life.

5. Boosting/Lessening/Throttling Modes

BOOSTING, LESSENING, and THROTTLING techniques are a kind ofreconfiguration of the battery cell array network or connection.BOOSTING raises up battery performance for urgent situations or sort ofthat require instantaneous output power/voltage increase from a batterysystem. In the BOOSTING battery mode, available regular and/or sparecells are additionally connected electrically to a given battery cellnetwork in serials and/or parallel, which enables quick increase involtage or power at the battery outputs. LESSENING is opposite toBOOSTING. LESSENING mode reconfigures the battery cell array network topush down battery performance for a non-busy moment that require lessoutput power or voltage from the battery.

The controller 150 is configured to allow the battery cell array 110 tobe reconfigured, and/or the charger selector array 120 and/or thebattery output array 140 to enable a spare or redundant battery cell(s)to be electrically and/or mechanically connected to a given battery cellnetwork in serials and/or parallel, wherein a battery cell(s) from theactive pool is already connected in serials and/or parallel, to achievequick increase in voltage or power at the battery outputs in BOOSTbattery mode.

The controller 150 is configured to allow the battery cell array 110 tobe reconfigured, and/or the charger selector 120 array and/or thebattery output array 140 to work with fewer active cells by electricallyand/or mechanically disconnecting an active cell(s) from a given batterycell network, wherein battery cells from the active pool are alreadyconnected in serials and/or parallel, to achieve quick decrease involtage or power at the battery outputs in LESSENING battery mode.

The controller 150 is configured to allow the battery cell array 110 tobe reconfigured, and/or the charger selector array 120 and/or thebattery output array 140 to work with fewer active cells or a differentbattery cell(s) available from other pools such as the charged pool orredundant pool by electrically and/or mechanically disconnecting anoverheated and active cell(s) and/or replacing an overheated and activecell(s) with a less-heated candidate cell(s) from other pools in a givenbattery cell network to achieve quick decrease in temperature based onthe temperature information reported from a temperature sensor(s) 160placed on a battery cell(s) and/or the battery system in thermalTHROTTLING battery mode.

Normally, neither excessive nor insufficient battery cells are activatedand a battery system provides a regular voltage and power to the finaloutput terminals. Availability of BOOSTING and or LESSENING modes mayfurther provide a way to use a battery device in an eco-friendly way.For example in EV applications, BOOSTING driving mode can provide anextra power for electrical vehicles to instantaneously speed up or drivea heavy load. LESSENING operation mode prevents the same battery devicefrom over-generating power and thus saves electric energy. LESSENINGmode dynamically reconfigures the battery cell network array to work inthe much less-power mode or more power-saving mode with fewer cellsconnected in series and/or parallel, for example, while underlyingapplications remain stationary and stay in idle times.

THROTTLINGING mode prevents a battery device from being overheated andthus saves the device. Excessive temperature may shorten battery's lifeor even permanently damage the battery itself. When a temperaturesensor(s) 160 gives temperature readings of around a certain threshold(say, 130° C.), the battery device starts throttling. A mechanicaland/or electrical temperature sensor(s) 160 may measure the body and/orambient temperature of an individual cell(s) and/or the entire batterydevice. Temperature information read from the sensor(s) may be reportedto the controller 150 and used for over-heated cell replacement(s)during the next cell accesses. This thermal THROTTLING mode may causethe overall battery performance like output voltage and powerperformance to be reduced.

It should be understood that the exemplary embodiments described thereinshould be considered in a descriptive sense only and not for purposes oflimitation. Descriptions of features or aspects within each embodimentshould typically be considered as available for other similar featuresor aspects in other embodiments.

What is claimed is:
 1. A battery cell array including: a plurality ofbattery banks, each battery bank including a two-dimensional m-by-n orhigher-order matrix of battery cells; a row address decoder configuredto activate selected address lines, the address lines including awordline(s); a column address decoder configured to activate selectedaddress lines, the address lines including a bitline(s); an addressdecoder(s), if required, configured to activate a select signal(s) toselect an additional address line(s) for a more than two-dimensionalmatrix of battery cells; a controller configured to directly orindirectly activate a bank select signal(s) to select a battery bank ofthe plurality of battery banks, wherein m is a number of rows and n is anumber of columns.
 2. The battery cell array of claim 1, wherein thecontroller is configured to newly redirect the charging and dischargingprocesses to a different battery cell(s) to avoid a premature wear-outof a heavily used battery cell(s).
 3. The battery cell array of claim 1,wherein the controller is configured to exclude an obsolete cell inselection as a normal cell for valid battery operation and replace theobsolete cell with a candidate cell(s) selected from a pool of redundantcells by reconfiguring the matrix of battery cells, and/or the chargerselector array and/or a battery output array accordingly.
 4. The batterycell array of claim 1, wherein the controller is configured to allow thebattery cell array to be configured, and/or charger selector arrayand/or the battery output array to enable a spare or redundant batterycell(s) to be electrically and/or mechanically connected to a givenbattery cell network in serials and/or parallel, wherein a batterycell(s) from the active pool is already connected in serials and/orparallel, to achieve quick increase in voltage or power at the batteryoutputs in BOOST battery mode.
 5. The battery cell array of claim 1,wherein the controller is configured to allow the battery cell array tobe reconfigured, and/or the charger selector array and/or the batteryoutput array to work with fewer active cells by electrically and/ormechanically disconnecting an active cell(s) from a given battery cellnetwork, wherein battery cells from the active pool are alreadyconnected in serials and/or parallel, to achieve quick decrease involtage or power at the battery outputs in LESSENING battery mode. 6.The battery cell array of claim 1, wherein the controller is configuredto allow the battery cell array to be reconfigured, and/or the chargerselector array and/or the battery output array to work with fewer activecells and/or a different battery cell(s) available from other pools suchas the charged pool or redundant pool by electrically and/ormechanically disconnecting an overheated active cell(s) and/or replacingan overheated active cell(s) with a less-heated candidate cell(s) fromthe other pools in a given battery cell network to achieve quickdecrease in temperature based on the temperature information reportedfrom a temperature sensor(s) placed on a battery cell(s) and/or thebattery system in thermal THROTTLING battery mode.
 7. The battery cellarray of claim 1, wherein the two-dimensional m-by-n or higher-ordermatrix of battery cells are traced and/or selected in a queue or pool,and a data structure for the queue or pool can be stored in eitheroff-device or on-device.
 8. The battery cell array of claim 1, whereinthe two-dimensional m-by-n or higher-order matrix of battery cells isconfigured to be classified into one of pools such as an active pool, adischarged pool and a charged pool, wherein the active pool consists ofbattery cells electrically charged, the battery cells being able toproviding electric power immediately, wherein the discharged poolconsists of battery cells deeply or shallowly discharged and requiringto be recharged to be active, wherein the charged pool consists ofbattery cells charged enough and ready to be active, when the batterycell is or gets faulty, the cell becomes an obsolete one excluded fromthe active, charged, and discharged pools mentioned above and/or maybebelonged to other pools including an obsolete pool further, ifnecessary.